Planar transformers provide simplified solutions for compact electrical devices and have a generally planar form incorporating a larger number of coils as a printed circuit than can be fit into the equivalent space of round cross-sectional wire. Planar printed circuits afford many design options, one of which allows the coil to take any shape and width. Wide conductors make higher current flow possible. Thin conductors significantly reduce the transformer's weight. Still, one inflexible aspect of such devices relates to the design of the turns ratio. Whereas round wire wound onto a core provides a certain degree of design flexibility, new printed circuits must be fabricated for each coil pattern desired resulting in additional time and cost.
In another aspect of planar transformers, it is known to provide insulation between conductor layers, e.g. circuit boards. Typically, a dielectric coating is applied to the circuit boards to prevent electrical contact between coils. Kapton® as manufactured by Dupont™ is one type of insulation used. However the thickness of the coating varies, particularly in the vicinity of irregular shapes or protrusions printed on the substrate. Some coatings can even become porous over time or after drying, allowing an electrical discharge when the circuit is in use.
A need exists for a planar transformer that is modular and that insulates the circuit boards to prevent electrical contact between conductive layers. One purpose of this invention is to provide such arrangements with its various attendant advantages.